58 lines
1.0 KiB
JavaScript
58 lines
1.0 KiB
JavaScript
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const fs = require('fs')
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const readline = require('readline');
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const readInterface = readline.createInterface({
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input: fs.createReadStream('input'),
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console: false
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});
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// array of arrays of bool. Coordinates are [y][x]. True = tree.
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let map = [];
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readInterface.on('line', function(line) {
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let row = [];
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line.split('').forEach(function(char) {
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if (char == '.') {
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row.push(false);
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} else if (char == '#') {
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row.push(true);
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}; // ignore any other character
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});
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map.push(row);
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});
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readInterface.on('close', function(line) {
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let totals = [];
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[[1,1], [3,1], [5,1], [7,1], [1,2]].forEach(function(step) {
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let treesHit = 0;
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let x = 0;
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let y = 0;
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while (y + 1 < map.length) {
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x += step[0];
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y += step[1];
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if (x + 1 > map[y].length) {
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x -= map[y].length;
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}
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if (map[y][x]) {
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treesHit++;
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}
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// console.log(x, y, map[y][x]);
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}
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totals.push(treesHit);
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});
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console.log(totals.reduce((a,b) => a * b));
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});
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